Field of the Invention
The present invention relates to an image capturing apparatus, an image capturing system, and a method for driving the image capturing apparatus.
Description of the Related Art
Japanese Patent Laid-Open No. 2010-259027 discloses an image capturing apparatus including a plurality of pixels disposed in a matrix form, a plurality of vertical signal lines each provided for a corresponding one of the columns of the pixels, to which signals are output from the pixels, and a plurality of current sources that supply current to the corresponding plurality of vertical signal lines.
FIG. 10 of Japanese Patent Laid-Open No. 2010-259027 shows a configuration in which each of the plurality of current sources includes a first current source and a second current source that is switched between an operating state and a non-operating state in response to a current selection signal. Japanese Patent Laid-Open No. 2010-259027 describes a first operation in which the first current source supplies current to the vertical signal lines and a second operation in which the first current source and the second current source supply current to the vertical signal lines. In each of the plurality of current sources, the first current source and the second current source are connected to a common connecting line.
With the configuration of the current sources disclosed in Japanese Patent Laid-Open No. 2010-259027, the common connecting line changes in electric potential due to switching of the second current source between an operating state and a non-operating state. The changes in the potential of the common connecting line are conveyed to the first current source that supplies current to the vertical signal lines. This causes changes in the amount of current that the first current source supplies to the vertical signal lines. The changes in the amount of current on the vertical signal lines can disadvantageously cause changes in signals output from the pixels to the vertical signal lines.